Quick releasing cross-brace latch for knock-down scaffolding



'Dec. 29, 1970 ALLEY 3,551,011

QUICK RELEASLNU CROSS-BEACH LATCH FOR KNOCK-DOWN SCAFFOLDIND Filed April 28, 1969 2 Sheets-Sheet 1 David W. Alley IN VE NTOR A T TORNEY Dec. 29, 1970 Filed April 28, 1969 D. w. ALLE Y 3,551,01fi

QUICK RELEASING CROSS-BRACE LATCH FOR KNOCK-DOWN SCAFF'OLDIND 2 Sheets-Sheet 2 David W. Alley INVENTOR ATTRNEY United States Patent O U.S. Cl. 287-535 7 Claims ABSTRACT OF THE DISCLOSURE A latch mechanism for use in releasably connecting the cross-braces to the uprights of a scaffolding structure of the knock-down type. The mechanism includes a crossbrace connecting pin extending horizontally from the upright upon which the perforated end of the cross-brace may be positioned, and a latch element slidable in a guide tube attached to the upright above the pin and extending downwardly at an angle to the horizontal, to allow the element to move downwardly by gravity into engagement at its lower end with the pin outwardly beyond the crossbrace to hold the cross-brace against disconnection from the pin. The latch element is moved upwardly out of latching position by engagement with the cross-brace as the cross-brace is pushed onto the pin and falls by gravity into latching position when the cross-brace has passed beneath the latch element. The latch element is lifted manually out of latching position when removing the cross-brace from the pin.

BACKGROUND OF THE INVENTION In the construction of scaffolding, it is customary to make use of spaced apart uprights connected together by cross-braces. Such scaffolding is usually made to be easily assembled and disassembled by providing the uprights with vertically spaced, horizontal pins upon which the perforated ends of the cross-braces may be removably placed.

In order to prevent disconnection of the cross-braces from the uprights, various kinds of latching or retaining devices have been employed heretofore which are operable to hold the cross-braces on the pins and which may be released to permit the cross-braces to be removed. As heretofore commonly provided; cross-brace latching mechanism in this type of scaffolding is exposed and unprotected against the accumulation thereon of rust, dirt, cement or the like, so that the latching mechanism may become clogged and inoperable, thus greatly interfering with the assembling or disassembling of the scaffolding. S'uch clogging often makes it necessary to pry or hammer the latching mechanism to release the same, resulting in breakage or damage to the same sufficient to render it permanently inoperable.

SUMMARY OF THE INVENTION Briefly described, the cross-braceilatching mechanism of the present invention comprises a horizontal pin extending from the upright of the scaffolding and a sliding, gravity actuated latching element, slidably disposed in a guide tube carried by the upright above the pin and sloping downwardly at an angleto the horizontal to position the element for engagement at its lower end with the pin at a location spaced outwardly from the cross-brace when the same is positioned on the pin to hold the cross-brace against removal from the pin.

The latch element is engageable at its lower end with the cross-brace as the cross-brace is moved into position on the pin to lift the element out of latching position to allow the cross-brace to pass beneath the element into position on the pin and the element then moves down- 3,551,0 1 1 Patented Dec. 29, 1970 ICE Wardly by gravity into latching position with its lower end in engagement with the pin.

In a preferred form of the invention, the guide tube is extended through an opening in the upright to position the upper end of the tube within the upright, and the upper end of the tube may be closed to prevent the entrance of foreign matter. Due to the downwardly sloping arrangement of the guide tube and latch element, foreign matter is prevented from clogging the latching mechanism.

The pin, guide tube and latch element may be formed as an integral structure, in a modified form of the invention, which structure is formed with an attaching base by which the mechanism may be attached as a unit to the upright with the upper end of the guide tube closed by the upright.

The latch mechanism is adapted to be released manually by lifting the latch element out of latching position to permit removal of the cross-brace from the pin.

BRIEF DESCRIPTION OF THE VIEWS OF THE DRAWINGS FIG. 1 is a fragmentary perspective view of a preferred embodiment of the cross-brace latching mechanism of the invention, showing the mechanism in its crossbrace latching condition;

FIG. 2 is a cross-sectional view, on a somewhat reduced scale, taken along the line 2-2 of FIG. 1, looking in the direction of the arrows, showing the latching mechanism prior to the connection of a cross-brace of the scaffolding to an upright of the same;

FIG. 3 is a view similar to that of FIG. 2 showing the latching mechanism during the connecting of the crossbrace to the upright;

FIG. 4 is a view similar to that of FIG. 2 showing the latching mechanism in its latching position with the cross-brace connected to the upright;

FIG. 5 is a view similar to that of FIG. 1, illustrating a modified form of the invention, showing the cross-brace latching mechanism with the cross-brace removed from the upright of the scaffold;

FIG. 6 is a cross-sectional view taken along the line 6d6 of FIG. 5, looking in the direction of the arrows; an

FIG. 7 is a cross-sectional view, taken along the line 7-7 of FIG. 6, looking in the direction of the arrows.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS OF THE INVENTION The invention is disclosed herein in connection with its application to a scaffolding of a conventional type having spaced apart tubular uprights, such as that indicated at 10, which are connected together by cross-brace members 12, which may also be of tubular structure having flattened end portions 14 which are perforated, or apertured, as shown at 16.

The uprights 10, in this type of structure, are provided with longitudinally spaced shanks or pins 18 extending horizontally therefrom, and which may be attached to the uprights in any suitable manner, as by welding, as seen at 20, or by threading, or otherwise, and upon which the perforated ends of the cross-brace members 12 may be positioned to connect the uprights together. The pins 18 are preferably formed with bevelled outer end portions 22 for convenience in inserting the pins through the perforations 16 of the cross-braces.

For the purpose of releasably retaining the cross-braces in position on the pins, latching mechanism is associated with each pin, which in the present illustration, takes the form of a guide tube 24, which is inserted through an opening 26 in the upright above the pin and which extends downwardly at an angle to the horizontal exteriorly of the upright with its lower end disposed in spaced relation to the pin at a distance to allow the flattened portion 14 of the cross-brace to be positioned on the pin without engagement with the guide tube. The guide tube may be attached to the upright in any suitable manner, as by welding as shown at 26. The upper end of the guide tube may be closed, if desired.

Within the guide tube 24 a gravity actuated latch element 28 is slidably disposed, whose lower end is positioned to engage the pin 18 at a location spaced from the outer end of the pin, when the element is in latching position, as shown in FIG. 4.

The element 28 is preferably shaped to conform to the internal shape of the guide tube and of a size to freely slide therein, and is formed with a flat end face 30 positioned to be engaged by the flattened portion 14 of the cross-brace to lift the element as the cross-brace is moved into position on the pin, as shown in FIG. 3, to allow the flattened end portion 14 of the cross-brace to pass beneath the pin, whereupon the element may then fall by gravity to the latching position of FIG. 4 to prevent the cross-brace from becoming detached from the pin.

In assembling a scaffold making use of the cross-brace latching mechanism of the invention, the uprights of the scaffold are placed at the proper distances apart and the cross-braces connected thereto by merely pushing the ends of the cross-braces onto the pins 18 to insert the pins in the perforations 16. As the end portion of the cross-brace moves onto the pin, the flattened end portion 14 engages the end face of the latch element 28 to lift the element to allow the cross-brace to pass beneath the element, which then returns by gravity to its latching position. Due to the downwardly extending, angular position of the element, the cross-brace is held against removal from the pin as long as the element is resting on the pin.

To remove the cross-brace, it is merely necessary to lift the element 28 manually and pull the cross brace off the pin.

It will thus be apparent that the invention provides cross-brace latching mechanism for knock-down scaffolding structures, by which the scaffolding may be easily and quickly assembled, the cross-braces being automatically securely locked in assembled relation with the uprights, and which permits the scaffold to be readily disassembled when desired.

Moreover, due to the downwardly angling position of the guide tube 24 and the positioning of the upper end of the tube within the upright, the guide tube is protected against the entrance of cement, dirt, or other material H likely to interfere with the free movement of the latch element 28. The upper end of the guide tube may also be closed to prevent the accidental entrance of dirt into the guide tube from above.

A somewhat different form of the invention is illustrated in FIGS. 5, 6 and 7, wherein the pin 18 and guide tube 24 are formed as an integral body, as by casting, or the like, each unit of which is formed with a base portion 32 which may be somewhat plate-like and having a curved face 34, best seen in FIG. 7, substantially conforming to the external curvature of the upright 10 and adapted to be seated thereon.

The body of the latch mechanism, in this form of the invention, may be applied to the upright by welding as shown at 36, or in some other suitable manner.

It will be seen that the guide tube portion 24 has a bore 3-8, shown in FIG. 6, in which the latching element 28' is slidable and movable by gravity into engagement at its lower end with the pin 18' and that the upper end of the bore will be closed by the upright when the mechanism is attached thereto.

Due to the integral, unitary structure of the latch mechanism of FIGS. 5, 6 and 7, and its mode of attachment to the upright, a very strong and rugged structure is provided which is unlikely to be damaged by rough useage or accidental striking against other objects.

The pins 18 and 18 may, of course, be of a length to permit the connection of more than one of the crossbrace 12 to the upright, as seen in FIG. 6.

In other respects, the form of the invention illustrated in FIGS. 5, 6 and 7 is similar to and functions in the same manner as that of FIGS. 1-4.

Having thus clearly shown and deseribed the invention, what is claimed as new and desired to secure by Letters Patent is:

1. A releasable cross-brace connection for a scaffold having spaced apart uprights and elongated cross-braces formed with perforations at their ends, comprising:

a laterally extending pin on each upright positioned to be extended through a perforation of one of said cross-braces; and,

a downwardly and laterally outwardly sloping, elongated la th element movably rmounted on the upright above said pin for longitudinal movement under the influence of gravity to a latching position for engagement with the cross-brace inwardly of the outer end of said pin to hold the cross-brace against movement off the pin, said element being engageable with the cross-brace when the element is in said latching position to move the element out of said latching position to allow the cross-brace to pass beneath the element upon movement of the cross-brace toward the upright to extend the pin through said perforation.

2. The cross-brace connection as claimed in claim 1 wherein said latch element is engageable with said pin at a location spaced outwardly from the upright beyond said cross-brace when the element is in said latching position.

3. The cross-brace connection as claimed in claim 1 including tubular guide means carried by said upright in which said latch element is slidably positioned.

4. The cross-brace connection as claimed in claim 3, wherein said upright is tubular and said guide means is extended into the interior of the upright.

5. The cross-brace connection as claimed in claim 3 including means closing the upper end of said guide means.

6. The cross-brace connection as claimed in claim 1 wherein said pin and guide means are formed in one piece adapted to be attached to the exterior of said upright.

7. The cross-brace connection as claimed in claim 6 wherein said upright is tubular having a cylindrical external surface, and wherein said pin and guide means is formed with a curved face conforming to the shape of and adapted to be seated against said external surface.

References Cited UNITED STATES PATENTS 2,620,237 12/1952 Kirkpatrick 52645 3,174,779 3/1965 Moritz 28753.5

3,345,655 10/1967 Juculano 28753.5X

3,361,447 1/ 1968 Englemann 28753.5X

FOREIGN PATENTS 1,010,030 6/1957 Germany 287-535 DAVID J. WILLIAMOWSKY, Primary Examiner W. L. SHEDD, Assistant Examiner US. Cl. X.R. 52 645 

